1. Field of the Invention
The invention relates to the field of systems and methods for determining transfer functions.
2. Prior Art
In modern technology it is sometimes desirable, and often necessary, to determine or approximate the transfer function of an object or specimen. The transfer function is used for structural analysis of aircraft, space vehicles and countless other structures; for vibration and environmental testing and in other applications. In many, if not most, practical applications, a theoretical determination of the transfer function of a complex structure may not readily be computed, and the transfer function, if obtainable, must be determined from empirical data. Typically, the structure is subjected to some known driving signal, such as an impulse, and the response of the structure is then measured. From a comparison of the input signal to the response signal the transfer function is then determined.
Generally, in the computation of transfer functions a predetermined segment of the input or driving signal is compared with a predetermined segment of response signal. In the prior art the input signal is often divided into a plurality of equal frames, as is the response signal, and input signals are compared with corresponding response signals for the calculation of the transfer function. Implicit in this comparison is that the response signals are a complete statement of the response to the driving signal. This simplifying assumption, while providing a convenient computational vehicle, introduces a considerable error into the calculation of the transfer function for many practical complex structures. The variances introduced in the computation by this simplifying assumption will be explained in greater detail in conjunction with FIGS. 1 and 2 in the detailed description of the invention.